Clues to obesity genes found

10th April 2012

International scientists have found two key genetic areas linked
to childhood obesity, suggesting that there is at least some inherited
component that explains why some people put on weight more easily than
others.

The researchers, who included a team at the Children's
Hospital of Philadelphia, carried out a genome-wide meta-analysis which
found two genetic factors that were common to all obese children in the
study.

While obesity, including the recent epidemic in richer
countries, is often blamed on eating too much and exercising too little,
researchers have now confirmed that our genes are at least partially to
blame.

Philidelphia researcher Struan Grant and colleagues,
writing in the online edition of Nature Genetics, said they had
pinpointed two new genetic variants which previously had never been
linked to obesity.

Grant said the research had confirmed that
obesity was not all about people's lifestyle choices, and that it was
possible to find a "genetic signature" for childhood obesity.

The
researchers chose to study children because there was less likelihood
that their obesity was caused by a lifetime of over-indulgence.

But
Grant said that the findings would still not be enough to explain the
huge rise in childhood obesity in recent decades, because human genetics
had not changed during that time period.

He said further research would be needed to investigate how genetics interacted with a child's environment.

But
childhood obesity experts said that while researchers now knew more,
clinical advice to parents and children would still be to eat more
healthily and to get plenty of exercise.

Keith-Thomas Ayoob of
Albert Einstein College of Medicine in New York City said the study, in
which he had no part, had not provided a magic bullet, and treatment
plans would remain the same.

The researchers conducted a
meta-analysis of date involving 5,530 children. The obese group were in
the top 5% of nationwide body mass index (BMI) measurements, while the
control group had BMI measurements that were in the bottom 50% in the
country.

The researchers aimed to add to what is currently already known about the genetic underpinning for adult obesity.

They
found that seven genetic areas already linked to adult obesity also
showed up in the children they studied. But when they focused more
closely on the data, they found eight new genetic signals, two of which
were significant for all humans.

The researchers then compared
the two new signal areas with the genetic data on 123,864 adult
participants in the GIANT Consortium long-term health study, and found
that both of their new signals were present, although not as strongly
present as in the children.

Very little is known about the newly
discovered genetic regions, except that they both have an effect on the
intestines. Neither genetic area has been implicated in obesity before,
and further research was needed to find out the mechanism through which
they act, Grant said.